vm5

diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
index 35552a6..26604d5 100644
--- a/sys/vm/vm_map.c
+++ b/sys/vm/vm_map.c
@@ -2972,6 +2972,26 @@ vmspace_map_entry_forked(const struct vmspace *vm1, struct vmspace *vm2,
 	}
 }
 
+static boolean_t
+vm_map_unmark_till_entry(vm_map_t map, vm_map_entry_t stop_entry)
+{
+	vm_map_entry_t entry;
+	boolean_t need_wakeup;
+
+	need_wakeup = FALSE;
+	for (entry = map->header.next; entry != stop_entry;
+	     entry = entry->next) {
+		KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0,
+		    ("Lost IN_TRANSITION"));
+		entry->eflags &= ~MAP_ENTRY_IN_TRANSITION;
+		if (entry->eflags & MAP_ENTRY_NEEDS_WAKEUP) {
+			entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP;
+			need_wakeup = TRUE;
+		}
+	}
+	return (need_wakeup);
+}
+
 /*
  * vmspace_fork:
  * Create a new process vmspace structure and vm_map
@@ -2989,15 +3009,31 @@ vmspace_fork(struct vmspace *vm1, vm_ooffset_t *fork_charge)
 	struct vmspace *vm2;
 	vm_map_t old_map = &vm1->vm_map;
 	vm_map_t new_map;
-	vm_map_entry_t old_entry;
-	vm_map_entry_t new_entry;
+	vm_map_entry_t entry, new_entry, old_entry;
 	vm_object_t object;
 	int locked;
+	boolean_t need_wakeup;
 
-	vm_map_lock(old_map);
+	need_wakeup = FALSE;
 	vm2 = vmspace_alloc(old_map->min_offset, old_map->max_offset);
 	if (vm2 == NULL)
 		goto unlock_and_return;
+
+mark_in_transition:
+	vm_map_lock(old_map);
+	for (entry = old_map->header.next; entry != &old_map->header;
+	     entry = entry->next) {
+		if (entry->eflags & MAP_ENTRY_IN_TRANSITION) {
+			need_wakeup = vm_map_unmark_till_entry(old_map, entry);
+			entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP;
+			if (need_wakeup)
+				vm_map_wakeup(old_map);
+			vm_map_unlock_and_wait(old_map, 0);
+			goto mark_in_transition;
+		}
+		entry->eflags |= MAP_ENTRY_IN_TRANSITION;
+	}
+
 	vm2->vm_taddr = vm1->vm_taddr;
 	vm2->vm_daddr = vm1->vm_daddr;
 	vm2->vm_maxsaddr = vm1->vm_maxsaddr;
@@ -3112,10 +3148,13 @@ vmspace_fork(struct vmspace *vm1, vm_ooffset_t *fork_charge)
 		}
 		old_entry = old_entry->next;
 	}
+	need_wakeup = vm_map_unmark_till_entry(old_map, &old_map->header);
 unlock_and_return:
 	vm_map_unlock(old_map);
 	if (vm2 != NULL)
 		vm_map_unlock(new_map);
+	if (need_wakeup)
+		vm_map_wakeup(old_map);
 
 	return (vm2);
 }